Sol-gel nanocomposite films as gas sensing and active optical materials

The University of Padua, Italy

Wednesday 15^th February 2006, 3.30PM, Seminar Room AR103, Graduate Research Centre.

Functional nanocomposite films have been obtained by doping sol-gel films with different functional nanoparticles. Highly luminescent waveguides have been obtained by doping ZrO₂-SiO₂ hybrid organic-inorganic sol-gel films with semiconductor quantum dots (CdSe, CdSe@CdS and CdSe@ZnS). Silver sensitised, erbium doped glass films have been synthesised using a combined sol-gel and ion exchange route. These films displayed different Er³⁺ photoluminescence behaviour depending on silver aggregation state. Nanoporous SiO₂ films doped with NiO or Co₃O₄ nanocrystals showed both optochemical and chemoresistive gas sensing properties. The nanoporosity of the sol-gel matrix provides a path for the gas molecules to reach the functional ultrafine particles embedded in the glass matrix, whereas the reacting metal oxide nanoparticles are responsible for the reversible change in resistance to different gases like H₂, CO and humidity, as well as a reversible change in the optical transmittance in the VIS-NIR range when exposed to CO.

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